For industrial robots, especially the ones designed to work in limited and complex workspaces, flexibility and compactness are among the major design requirements.
A robot typically comprises one or more rotary joints in order to achieve flexible positioning of robot arms. Generally, the larger the rotation ranges of rotary joints are, the more flexible a robot is. However, in order to transmit power and various signals to and from robot arms, one or more cables typically go through each rotary joint, and these cables cannot bear too much bending and twisting for a long time, which has become one of the major difficulties for large rotation ranges of rotary joints.
In addition, at each rotary joint, cables and hoses were usually put together to pass through either a tube shaft or a hollow gear, which then requires either bigger shaft or gear, contradict to the compact design demand, or requires customized gear, leading to high cost.
In view of the foregoing, there is a need in the art to develop an improved rotary joint and an improved routing structure.